(a) Impact fees assessed against a development project to fund capital improvements and public services may not exceed the actual proportionate share of any benefit realized by such project relative to the benefit to the resident taxpayers.

Notwithstanding any other provision of this code to the contrary, those counties that meet the requirements of section six of this article are hereby authorized to assess, levy, collect and administer any tax or fee as has been or may be specifically authorized by the Legislature by general law to the municipalities of this state: Provided, That any assessment, levy or collection shall be delayed sixty days from its regular effective date: Provided, however, That in the event fifteen percent of the qualified voters of the county by petition duly signed by them in their own handwriting and filed with the county commission within forty-five days after any impact fee or levy is imposed by the county commission, pursuant to this article, the fee or levy protested may not become effective until it is ratified by a majority of the legal votes cast thereon by the qualified voters of such county at any primary, general or special election as the county commission directs. Voting thereon may not take place until after notice of the subcommission of the fee a levy on the ballot has been given by publication of class II legal advertisement and publication area shall be the county where such fee or levy is imposed: Provided further, That counties may not "double tax" by applying a given tax within any corporate boundary in which that municipality has implemented such tax. Any such taxes or fees collected under this law may be used to fund a proportionate share of the cost of existing capital improvements and public services where it is shown that all or a portion of existing capital improvements and public services were provided in anticipation of the needs of new development.

(b) In determining a proportionate share of capital improvements and public services costs, the following factors shall be considered:

(1) The need for new capital improvements and public services to serve new development based on an existing capital improvements plan that shows (A) any current deficiencies in existing capital improvements and services that serve existing development and the means by which any such deficiencies may be eliminated within a reasonable period of time by means other than impact fees or additional levies; and (B) any additional demands reasonably anticipated as the result of capital improvements and public services created by new development;

(2) The availability of other sources of revenue to fund capital improvements and public services, including user charges, existing taxes, intergovernmental transfers, in addition to any special tax or assessment alternatives that may exist;

(3) The cost of existing capital improvements and public services;

(4) The method by which the existing capital improvements and public services are financed;

(5) The extent to which any new development, required to pay impact fees, has contributed to the cost of existing capital improvements and public services in order to determine if any credit or offset may be due such development as a result thereof;

(6) The extent to which any new development, required to pay impact fees, is reasonably projected to contribute to the cost of the existing capital improvements and public services in the future through user fees, debt service payments, or other necessary payments related to funding the cost of existing capital improvements and public services;

(7) The extent to which any new development is required, as a condition of approval, to construct and dedicate capital improvements and public services which may give rise to the future accrual of any credit or offsetting contribution; and

(8) The time-price differentials inherent in reasonably determining amounts paid and benefits received at various times that may give rise to the accrual of credits or offsets due new development as a result of past payments.

(c) Each county shall assess impact fees pursuant to a standard formula so as to ensure fair and similar treatment to all affected persons or projects. A county commission may provide partial or total funding from general or other nonimpact fee funding sources for capital improvements and public services directly related to new development, when such development benefits some public purpose, such as providing affordable housing and creating or retaining employment in the community.